January 31, 2022

Olivares Beta and Gamma Glaciers, Chile Bare of Snowcover in 2022

Posted by Mauri Pelto

Olivares Beta (B) and Olivares Gamma (G) Glacier in Sentinel image from 1-23-2022, illustrating the lack of retained snowcover with 8 weeks left in the melt season. The yellow arrow marks proglacial lakes below each glacier. The red arrow an area of emerging bedrock on the upper Beta, X marks a location where the glaciers were joined in 1986 and now have separated. 

Olivares Beta and Olivares Gamma Glacier are adjacent glaciers 50 km NE of Santiago Chile in the central Andes of Chile. The glaciers are at the headwaters of the Olivares River, which drains into the Coloardo River. The Alfalfal Hydropower Planton the Colorado River is a 178 MW run of river plant completed in 1991 and owned by AES Andes. Malmros et al (2016) identified the retreat and area change of te Olivares glaciers for the 1955-2013 period. They noted a retreat of 979 m from 1955-1994 on Olivares Beta and 753 m on Olivares Gamma Glacier. The identified area loss from 1955-2013 was 21% on Olivares Beta and 34% Olivares Gamma.  Dussaillant et al (2019) identified a slower mass loss  -0.28 m/year in this region from 2000-2018, than further south in the Patagonia Andes or north in the Tropical Andes. Here we examine Landsat imagery from 1986-2020 and Sentinel Imagery from 2020-2022 to identify changes in area and snowcover.  The lack of retained snowcover indicates mass balance losses which will drive further retreat.

Olivares Beta (B) and Olivares Gamma (G) Glacier in Landsat images from 1986, 1993, 2015 and 2020. The yellow arrow marks the terminus location in 1993 of both glaciers, the red arrow an area of emerging bedrock on the upper Beta, X marks a location where the glaciers were joined in 1986 and now have separated. 

In  1986 and 1993 both glaciers terminated in small proglacial lakes, yellow arrows, and were connected adjacent to Point X.  There is no evident bedrock emerging on the upper Beta. In 1986 there is limited retained snowcover, ~10% of total area by early March. In 1993 there is 30% snowcover on the glaciers in March. By 2015 the glacier had receded from the proglacial lakes, bedrock is emerging at the red arrow on the upper Beta, and the glaciers are barely connected at Point X. Snowcover is ~10% of total area in mid-February.  In 2020 the glaciers have disconnected at Point X and there is less than ~10% retained snowcover by mid-February. The proglacial lakes are also quite brown suggesting high runoff from the dirtier/darker glacier. By January 23, 2022 both glaciers have again lost almost all snowcover with 8 weeks left in the melt season. The dirtier firn and ice at the surface melts at a faster rate than snow for the same weather conditions.  The result will be large mass balance losses in 2022 that will further lead to glacier thinning and recession. Both glaciers currently extend from ~3800 m to ~4800 m, with areas below 4600 m consistently being in the ablation zone.

The early loss of snowcover has been seen on other nearby glaciers Cortaderal Glacier, Chile and Volcan Overo, Argentina due to the unsually warm conditions in the region, particularly in the first half of January.

Olivares Beta (B) and Olivares Gamma (G) Glacier in Sentinel image from 2-18-2020 illustrating the lack of retained snowcover with 4 weeks left in the melt season. The yellow arrow marks proglacial lakes below each glacier. The red arrow an area of emerging bedrock on the upper Beta, X marks a location where the glaciers were joined in 1986 and now have separated. 

Olivares Beta and Olivares Gamm